1. Field of the Invention
This invention relates to a building material, and more specifically to a building material which has absorption properties with respect to light of a specific wavelength (specific wavelength light) unique to the copper ion, and which has absorption properties with respect to light of wavelength from the near-infrared region to the infrared region and the ultraviolet region.
2. Related Background of the Invention
One example of a prior art optical material using the specific wavelength light absorption properties of copper ions is the material comprising an optical filter disclosed in Japanese Patent Application Laid-Open No. 6-118228 submitted by the Applicant. This special optical material contains a phosphoric ester, and has excellent absorption properties with respect to wavelengths from the near-infrared region to the infrared region (hereafter, infrared light absorption properties).